This is just an update on the situation if anyone's interested: Setsuna is sending me screenshots containing text and I'm translating them. I've done translation work before for fansubbing groups and I'm glad to be able to contribute to promoting and supporting IM@S for English-speakers.

Here is what I've got so far as of today as an example. I'm not sure how exactly this will help, but maybe someday a completely comprehensive English script can be made available for IM@S2?

Ar-39: "Huggy Toro" = "[Together no matter what] series is the motif here. Together even on stage-meow!"
Note: Toro = (white cat meme/mascot especially popular on 2ch)
Ar-40: "Cow Hooves" = "An item from the cow set. Since ancient times, the cow has been a symbol of strength. Share in the luck of such powerful strength."
Ar-41: "Idol Academy First Place Trophy" = "An item from the Idol Academy First Place set. Only those who shined as First Place winners can hold this trophy of highest honor in her hand."
Bd-39 "Cow Tail" = "An item from the cow set. The tail has the job of helping the body keep balance. With this your dance couldn't be 'moo'-re perfect!"
Note: There's a Japanese pun on the sound a cow makes, transliterated with the "moo" sound for cows in English.
Bd-40 "Idol Academy First Place Gold Medal" = "An item from the Idol Academy First Place set. Only those who were chosen are permitted to wear and display the honor of this medal."
EXT-28 "Forever Star" = "The hope that someday my hands can reach that glittering world of stars... Those wishes were crafted into this dress."
FLO-21 "Tulip Field" = "Like a field of flowers in full bloom with all the colors of the rainbow is the image that's presented. The language of flowers is love for all."
Hd-42 "Cow Ears" = "An item from the cow set. Cows are a symbol of an abundant harvest. Hopefully it will bring many blessings to the stage."
Hd-43 "Idol Academy Crown" = "An item from the Idol Academy First Place set. A prestigious laurel worthy of the Idol Academy First Place winner."
Hd-44 "Miss Kotori's Glossy Beauty Spot" = "Hehehe... With this everyone will be bewitched by me and then... I just can't stop imagining all the possibilties!"
Lg-39 "Cow Feet" = "An item from the cow set. Like a cow that can walk a thousand miles, if you keep going and don't give up, your dreams can come true!"
Lg-40 "Idol Academy Ribbon Garter" = "An item from the Idol Academy First Place set. Only First Place recipients can wear this garter ribbon."
LUX-21 "Monochrome Cowgirl" = "A cowgirl watching over a carefree young calf chewing on grass is the image meant for this outfit."
Song-27 "We'll always be together... right?" or "Watashi-tachi wa zutto... deshou?"
St-36: "Eternal Big Tree"
STA-21: "Violent Lightning" = "If you happen to see this dress, then you'll feel like you've been struck by brilliant purple lightning, and will be completely fixated on the stage.